Half spacing escapement mechanism



June 2, 1970 mx ET AL HALF SPACING ESCAPEMENT MECHANISM 2 Sheets-Sheet 1 Filed May 24, 1.968

fiNVENTOR '7,

r 4 ATTORNEY June 2, 1970 A. RIX ET AL HALF SPACING ESCAPEMENT MECHANISM Filed May 24, 1968 L y/ NM KNINlyVENjI'OR 4. V ATTORNEY) United States Patent HALF SPACING ESCAPEMENT MECHANISM Albert Rix, Siegfried Rciners, l-lelmut Ressel, and Manfred Voigt, Wilhelmshaven, Germany, assignors to Olympia Werke AG, Wilhelmshaven, Germany Filed May 24-, 1968, Ser. No. 731,874 Claims priority, application Gigrmany, May 26, 1967,

int. Cl. M13 19/58 US. Cl. 19784 11 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION The present invention relates to a half spacing escapement mechanism of the type in which the paper carriage of a business machine is held in an intermediate half spacing position by the depressed space bar, and is permitted to move to the end of a full step when the space bar is released.

The co-pending patent application Ser. No. 543,865, now US. Pat. No. 3,385,415, discloses a half spacing mechanism in which a control member, operated from the space bar or universal bar of a typewriter, actuates an escapement pawl to permit either a full carriage step if a type key or the space bar is shortly actuated, or to block carriage movement after half a step if the space bar is held in the depressed position. The construction is rather complicated, and the parts are difficult to assemble.

SUMMARY OF THE INVENTION It is one object of the invention to improve the half spacing mechanism according to the prior art, and to provide a half spacing escapement mechanism of simple and inexpensive construction which can be quickly assembled by an unskilled worker.

Another object of the invention is to provide a half spacing mechanism in which the movable parts are mounted on the supporting parts without any pivot pins, journals, and bearings for the journals.

Another object of the invention is to provide a half spacing escapement mechanism in which the movable parts are slidingly confined between two cover plates and mounted for angular movement in recesses of a spacing member between the cover plates.

Another object of the invention is to provide a half spacing escapement mechanism which is assembled by screwing two cover plates and a spacing member together, and placing all movable parts between the cover plates.

With these objects in view, one embodiment of the invention comprises a pawl having a projection for engaging the teeth of the rack bar of a paper carriage which is biased to move in one direction; support means having first and second open recesses mounting the pawl and a control member for angular movement; actuating means for connecting the control member with the space bar and the universal bar of a typewriter; and cover means on opposite sides of the support means so that a control member and a pawl are laterally and slidingly guided by 3,515,252 Patented June 2, 1970 the cover means while turning in the first and second recesses.

Due to the fact that support portions of the pawl and of the control member are turnably mounted in recesses of the support means, no pivots, journals, and bearings for the same are required, and the mechanism can be quickly assembled.

In the preferred embodiment of the invention, the cover means are two cover plates separated a small distance by a supporting spacing member which has the first and second recesses for movably supporting the pawl and the control member, respectively. The pawl and the control member are flat plate-shaped elements whose lateral faces are slidingly guided between the inner surfaces of the cover plates.

The pawl is biased by a spring to engage the teeth of the rack bar of the carriage, and the control member acts on the pawl to move the same to a position disengaged from the rack bar and tending to move into another notch of the same.

When the space bar is held in a depressed position, and the control member thereby is held in an actuated position, the rack bar and carriage are released, but since a control portion of the control member is located in the path of movement of a co-operating control portion of the pawl, the carriage is blocked after half a step. Upon release of the rack bar, the control member returns to its normal position out of the path of the control portion of the pawl so that the same is returned by the carriage spring to a normal first end position in which the pawl is blocked by a stop wall of the recess in which it is mounted.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation of a half spacing escapement mechanism of the invention in a first operation position;

FIG. 2 is a side elevation of the mechanism of FIG. 1 in a half spacing position and without the front cover plate; and

FIG. 3 is a perspective exploded view of the mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A housing has two parallel cover plates 2 and 4 screwed together by screws 5 and 5a which pass through bores of a spacing member 3. Cover plate 2 has a portion 2a, and cover plate 4 has two portions 4a which may be used for mounting the housing.

A paper carriage, of which only a portion 25 supporting a rack bar 23 is shown, is biased by the conventional carriage spring, not shown, to move in the direction of the arrow 23a in a writing direction.

A spacing member 3 and the gap between cover plates 2 and 4, are located directly under the rack bar 23.

Spacing member 3 has a first recess 15 bounded by stop walls or stop edges 13 and 14 and having a bottom face extending in the direction of the rack bar and carriage movement. Spacing member 3 has also a part circular second recess 17 from which a stop face 17a extends.

An escapement pawl 7 has a projection '6 which cooperates with the teeth of rack bar 23. The other end of pawl 6 has a support portion 12 located in recess 15 and being movable in the same. Pawl 7 is connected by spring 9 engaging a hole 7a to a fixed stud 8 which is positioned higher than the hole 7a so that projection 6 is urged upward into engagement with tooth 24. In a normal position of the mechanism shown in FIG. 1, the carriage spring, not shown, pulls rack bar 23 in the direction of the arrow 23a so that projection 6 and escapement pawl 7 are urged in the same direction until the stop edge 12a of support portion 12 of pawl 7 abuts the stop wall edge 13 of recess 15. Spring 9 urges pawl 7 in the opposite direction, but is too weak to overcome the strong force of the carriage spring. The inner surfaces of cover plates 2 and 3 slidingly guide and confine the pawl 7, and due to the abutment of projection 6 on tooth 24, pawl 7 cannot fall out of the housing 2, 3. Escapement pawl 7 has a control portion 10 ending in a flat abutment face 10a and having a slanted edge 11 bounding one side of a recess 11a.

A control member 19 is also mounted between the cover plates 2 and 4, and has an arm 19a ending in a part-circular support portion 18 which is located in a corresponding part-circular bearing recess 17 of spacing member 3 so that control member 19 is mounted in recess 17 for angular movement between a normal position shown in FIG. 1 in which arm 19a abuts edge 17a, and an actuated position in which the main part of control member 19 abuts a stop edge 16 of spacing members 3.

Control member 19 has a control portion 21 normally projecting into recess 11a, and having a slanted face 22 confronting the slanted face 11 of the control portion 10 of pawl 7.

Control member 19 is operated between the normal position abutting stop edge 17a, as shown in FIG. 1, and an actuated position abutting stop edge 16, by actuating means 20 which is connected to, and operated by, the standard universal bar of the typewriter and also by the standard space bar of the typewriter. When the space bar is not depressed, and no key is actuated, the universal bar, not shown, assumes a position for holding control member 19 in the normal position shown in FIG. 1 due to the action of a spring, not shown.

When the space bar is depresed, the actuating means 20 is operated to move control member 19 to the actuated position shown in FIG. 2, and as long as the space bar is held depressed, actuating member 19 remains in the actuated position of FIG. 2. Upon release of the space bar, actuating means 20 is shifted to return control member 19 to the normal position of FIG. 1. When a key is operated, the universal bar, not shown, operates the actuating member 20 to move control member 19 quickly to the actuated position shown in FIG. 2, and back again to the normal position shown in FIG. 1.

Control member 19 is a fiat plate which is slidingly guided between the two cover plates 2 and 4, and is supported by the bearing recess 17 for angular movement between the normal and actuated positions thereof.

OPERATION When the space bar is depressed, actuating means 20 pulls control member 19 to its actuated position shown in FIG. 2. Shortly after the start of this movement, the slanted face 22 of control portion 21 slidingly engages the slanted face 11 of control portion 10 of pawl 7 due to the overlapping of control portions 11a and 10 clearly shown in FIG. 1. During further downward movement of control member 19, the sliding of the slanted faces 22, 11 on each other causes an angular displacement of escapement pawl 7 in counterclockwise direction so that projection 6 releases tooth 24 of rack bar 23. Before the carriage can move a substantial distance, spring 9 pulls escapement pawl 7 from the first end position shown in FIG. 1 to the right and upward as viewed in the drawing so that projection 6 falls into the next-following notch of the rack bar and is engaged by the flank of the next following tooth 24.

The force of the carriage spring acting in the direction of the arrow 23a again overcomes the force of spring 9, and pawl 7 moves towards the left as viewed in the drawing.

In the event that the space bar is held depressed, control portion 21 is located in the path of movement of abutment face 10a of control portion 10, and consequently stops movement of escapement pawl 7, rack bar 23, and carriage 25. The force of the carriage spring is transmitted through the oppositely projecting portions 21 and 19a of control member 19 to the bearing recess 17 of spacing and supporting member 3 so that the carriage stops. The dimensions of control portions 10 and 21 are selected so that the carriage moves a small step which is preferably half the distance between two teeth 24, 24' which distance corresponds to a full carriage step.

When the pawls of the escapement mechanism are in the position of FIG. 2, the carriage is stopped between two normal positions, and it is possible to insert a letter in the space between two adjacent normally spaced letters for the purpose of correcting a word.

When the space bar is released in the position of FIG. 2, actuating means 20 is shifted to a position in which control portion 21 of control member 19 releases the endface 10a so that the force of the carriage spring, not shown, becomes effective to pull the carriage 25 with rack bar 23 and escapement pawl 7 in the direction of the arrow 23a while the parts of escapement pawl 7 bounding recess 11a move on opposite sides of the control portion 21 until the normal position shown in FIG. 1 is again established. In this position, the endface 12a of support portion 12 of pawl 7 abuts stop edge 13 of recess 15 so that the carriage is again stopped. The spacing between stop edge 12a of support portion 12 and stop edge 13 of recess 15 is selected so that the carriage moves another half step until blocked in the position of FIG. 1, in which the carriage has performed a full carriage step in the writing direction.

If the space bar is immediately released after depression, or if control member 19 is actuated by the universal bar which also immediately releases control member 19 after moving the same to the position of FIG. 2, control member 19 moves immediately back from the position of FIG. 2 to the position of FIG. 1 so that control portion 21 is not located in the path of movement of control portion 10 when the carriage and rack bar start the movement of the pawl toward the left, and the recess 11 permits movement of the escapement pawl 7 without blocking by control portion 21 for a full carriage step until stop edge 12a of support portion 12 abuts stop edge 13 of recess 15 in spacing member 3.

From the above description it will be apparent that the present invention provides a fully operative half spacing escapement mechanism Without using a single pivot pin or cylindrical bearing means for mounting the escapement pawl and the control member for angular movement. During assembly, the spacing member 3 is placed on one of the cover plates, the control member 19 and escapement pawl 7 are placed in recesses 17 and 15, and the second cover plate is screwed by screws 5 and 5a to to spacing member and the first cover plate. The device is now mounted on the typewriter frame, spring 9 hooked into hole 7a, and projection 6 placed in a recess of rack bar 23. Control member .19 is connected by actuating means 20 to the space bar and universal bar of the typewriter, and the escapement mechanism is ready for operation.

Due to the extreme simplicity of the assembly, a great deal of assembly time is saved, and the control member 19 and pawl 7 are inexpensive flat parts stamped of plate material.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of escapement mechanisms differing from the types described above.

While the invention has been illustrated and described as embodied in an escapement mechanism whose movable parts are mounted for turning movement Without the use of journals and bearings so that the device can be easily assembled, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can be applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. A half spacing escapement mechanism for the carriage of a business machine, comprising, in combination, carriage means biassed to move in one direction and including gear means having teeth; a pawl having a projection for engaging said teeth, a first support portion, and a first control portion; support means having first and second open recesses, said first recess being bounded by a stop wall and receiving said first support portion for mounting said pawl for turning movement toward and away from said gear means between a releasing position spaced from said teeth and an engaging position in which said projection engages a tooth, and also for movement substantially parallel to said one direction between first and second end positions, said pawl in said engaging position being urged by said biassed gear means to move to said first end position while said first control portion moves along a predetermined path until said first support portion abuts said stop wall of said support means for blocking movement of said carriage means after a full carriage step; a control member having a second support portion located in said second recess for mounting said control member for angular movement between a normal position and an actuated position and having a second control portion located outside of said path in said position and in said path in said actuated position of said control member, said first and second control portions cooperating with each other in said first end position of said pawl so that said control member turning from said normal position to said actuated position turns said pawl from said engaging position to said releasing position; spring means biassing said pawl to move to said second end position and to said engaging position for engaging the next following tooth so that said first and second control portions are located in said path spaced half a step of said carriage means when said control member is in said actuated position; actuating means for connecting said control member with a space bar so that by operation of said actuating means said control member can be held in said actuated position whereby said carriage means is stopped after half a carriage step, and can be held in said normal position so that said second portion is located out of said path so that said carriage means moves a full carriage step; and cover means on opposite sides of said support means, said cover means being spaced from each other by said support means for laterally guiding said control member and said pawl whereby no pivots are required for mounting the same.

2. Escapement mechanism as claimed in claim 1 wherein said cover means include two cover plates; and wherein said support means include spacing means for spacing 6 said cover plates a predetermined distance and being secured to the same; and wherein said pawl and said control member are flat and have a thickness slightly less than said spacing means so as to be movably guided and confined by said cover plates.

3. Escapement mechanism as claimed in claim 2 wherein said projection of said pawl is located outside of said cover plates in said engaging position and abuts said gear means for retaining said pawl between said cover plates against the action of said spring means.

4. Escapement mechanism as claimed in claim 2 wherein said spacing means includes a spacing plate having said first and second recesses.

5. Escapement mechanism as claimed in claim 4 wherein said spacing plate has said first and second recesses, and a stop face extending from said second recess engaged by said control member in said normal position of the same.

6. Escapement mechanism as claimed in claim 1 wherein said second support portion of said control member is part-circular; and wherein said second recess is partcircular and turnably mounts said part-circular support portion.

7. Escapement mechanism as claimed in claim 1 wherein said first recess is substantially rectangular and has lateral edges formed by said stop wall, and a bottom edge, and wherein said first support portion slidingly engages said bottom edge during movement of said pawl to said first end position until stopped by one of said lateral edges.

8. Escapement mechanism as claimed in claim 1 wherein said cover means include two cover plates; and wherein said support means include spacing means for spacing said cover plates a predetermined distance and being secured to the same; wherein said pawl and said control member are fiat and have a thickness slightly less than said spacing means so as to be movably guided and confined by said cover plates; wherein said spacing means has said first and second recesses; wherein said first recess is substantially rectangular; wherein said second recess is part-circular; and wherein said first support portion is smaller than said first recess and slidingly guided in the same; and wherein said second support portion is partcircular and turnably mounted in said part-circular second recess.

9. Escapement mechanism as claimed in claim 1 wherein said control member has a main part having two ends, said second control portion and said second support portion projecting in opposite directions from one of said ends, and said actuating means being connected with the other end of said main part.

10. Escapement mechanism as claimed in claim 1 wherein said first and second control portions are in an overlapping position overlapping each other when said control member is in said normal position and said pawl is in said first end position, and have first and second slanted faces confronting each other in said overlapping position.

11. A half spacing escapement mechanism for the carriage of a business machine, comprising, in combination, carriage means biassed to move in one direction and including gear means havng teeth; a housing including two spaced cover plates forming a gap, and a spacing member between the same, said spacing member having first and second recesses and being secured to said cover plates; a pawl mounted in said gap for movement in said first recess laterally guided by said cover plates; spring means biassing said pawl to engage said gear means; and a control means mounted in said gap for movement in said second recess, being operable from a normal position to an actuated position for moving said pawl from a position engaging a tooth of said gear means to a position releasing said tooth and operated by said spring means to engage another tooth so that said pawl is moved by said carriage means until stopped by said control means 7 8 in said actuated position after half a carriage step, or 3,232,405 2/1966 Walton. by said spacing member after a full carriage step if said 3,385,415 5/1968 Shrader et a1. control means is returned to a normal position. 3,455,429 7/ 1969 Schweizer.

References Cited 5 ROBERT E. PULFREY, Primary Examiner UNITED STATES PATENTS S. C. PELLEGRINO, Assistant Examiner 2,536,619 1/1951 Yaeger. 2,862,595 12/1958 Toggenburger.

2,955,695 10/1960 Ling. 197-86 

